Spinal and Joint Injections
many cases of chronic back pain, spinal injections are used both to
learn more about what is causing your pain and to treat your pain.
Health care providers refer to these two separate uses of spinal
injections as diagnostic and therapeutic. The injections can be a
diagnostic tool because they give your doctor information that helps him
or her make a diagnosis. For example, if an injection provides pain
relief in the area that is injected, it is likely that this particular
area is the source of the problem. Once the location of one or more
sources of pain is discovered, your health care provider can perform
other necessary tests to try to determine the actual problem and create
the proper treatment plan. The injections are therapeutic in that they
can provide temporary treatment and pain relief.
What medications are injected and why?
most spinal injections, a local anesthetic (numbing medication) called
lidocaine, also known as Xylocaine, is injected into a specific area of
the spine. Lidocaine is a fast-acting drug, but the effects wear off
within about two hours. Therefore, this medication is used more as a
diagnostic tool rather than as a long-lasting pain reliever. Another
type of anesthetic, called Bupivacaine, also known as Marcaine, can also
be used. This anesthetic takes longer to take effect, but it also wears
off slower, giving the patient some relief from pain.
strong anti-inflammatory steroid medication, cortisone, is also
commonly injected along with one of the above anesthetics in order to
reduce inflammation in the affected areas. Cortisone is long-lasting and
can be slow-releasing in order to give the best possible benefits of
pain relief. Cortisone may take several days to begin working to reduce
inflammation following injection, but the effects can last for months.
In some cases, a narcotic medication such as morphine or fentanyl may be
mixed with the cortisone and the anesthetic in order to improve pain
Types of Injections and Why They Are Done
Epidural Steroid Injection:
steroid injection (ESI) is a common type of injection that is
given to provide relief from lower back pain and from certain types of
neck pain. The epidural space is the space between the spinal sac
(called the dura mater) and the inside of the bony spinal canal. It runs
the entire length of your spine. Once injected into this area, the
medication moves freely up and down the spine to coat the nerve roots
and the outside lining of the facet joints of the spine near the area of
injection. For example, if the injection is done in the lumbar spine,
the medication will usually affect the entire lower portion of the
There are three different ways to perform an epidural injection:
- Caudal Block: A caudal block is placed through the sacral
gap (a space near the sacrum and below the lumbar spine), into the
epidural space. This type of block usually affects the spinal nerves
that are at the end of the spinal cord near the sacrum (near the
bottom). This collection of nerves is also called the cauda equina. One
of the benefits of this type of injection is less chance of a dural
puncture, also called a "wet tap." As mentioned above, the dura mater is
the spinal sac, the membrane that holds the spinal fluid and protects
the cord and nerves from damage.
- Translumbar: The most common way of performing an epidural
is the translumbar approach. This type of injection is performed by
placing a needle between two vertebrae from the back. The needle is
inserted between the spinous processes of the two vertebrae. You can
usually feel the bumps that make up the spinous process by simply
feeling the back of your spine.
- Transforaminal: This type of injection is a very selective
injection around a specific nerve root. It is most often used for
diagnostic purposes, and it is commonly used in the neck. The foramina
are the small openings between your vertebrae through which the nerve
roots exit the spinal canal and enter the body. By injecting medication
only around a specific nerve root, the doctor can determine if this is
the nerve root causing the problem.
Indications to use an epidural:
It may be necessary to have several epidural injections
in a series over a period for a few weeks. This is because the relief
from the epidural injection decreases with time. It is not uncommon to
have three lumbar epidural injections, each about ten days apart.
injections are good for reducing radicular pain caused by nerve
irritation from herniated discs and spinal stenosis. A herniated disc
occurs when pressure to a disc's outer fibers (annulus) is so great that
it rips, and the nucleus ruptures out of its normal space. If it rips
near the spinal canal, the bulging disc can push out of its space and
into the spinal canal, placing inappropriate pressure on the spinal cord
and nerve roots. Spinal stenosis is basically a narrowing of the entire
spinal canal, which places pressure on the nerves and spinal cord. The
injections are also helpful when the main problem is arthritis of the
facet joints in multiple areas. The medication coats the outside of the
joints at multiple levels and is absorbed into the joint. This reduces
the inflammation inside the joint.
any surgery, there is a risk of complications. When surgery is done
near the spine and spinal cord these complications (if they occur) can
be very serious. Complications could involve subsequent pain and
impairment and the need for additional surgery. You should discuss the
complications associated with surgery with your doctor before surgery.
The list of complications provided here is not intended to be a complete
list of complications and is not a substitute for discussing the risks
of surgery with your doctor. Only your doctor can evaluate your
condition and inform you of the risks of any medical treatment he or she
A dural puncture ("wet tap") is perhaps the most common complication
from an ESI. This complication only occurs in 0.1 to 5 percent of all
injections. The result of a dural puncture is usually a spinal headache
and nausea. A spinal headache occurs when the puncture in the
spinal sac fails to seal itself off. This allows the spinal fluid to
continue to leak out and lowers the spinal fluid pressure in the brain.
When sitting, the headache and nausea are much worse, because the spinal
fluid pressure is lower at the top, near your head, than at the bottom
of the spine. The headache usually goes away when you lie down with your
feet higher than your head. To treat a spinal headache, a "blood patch"
is usually recommended. If the doctor realizes immediately during the
procedure he has a wet tap, he may perform a blood patch before he
removes the epidural needle. A blood patch is a simple procedure in
which about three ounces of blood are drawn from an arm vein and
immediately injected into the epidural space with an epidural needle.
The blood then clots around the spinal sac and stops the leak by forming
Intravascular Injection: There
is a small chance that the medication may be injected into one of the
small blood vessels that run through the epidural space instead of the
epidural space itself. This can cause seizures, cardiac arrest, and even
death if too much of the medication goes directly into the blood
stream. The chance of this happening is very low. Your doctor can
discuss it with you in further detail.
injections are done under sterile conditions very similar to surgery.
Still, anytime a needle is inserted into the body there is a small
chance of infection. Since the needle in an epidural is going near the
spine, an infection is much more serious if it occurs. The chance that
an infection will occur is extremely small.
epidural injection can result in a hematoma. A hematoma is simply a
collection of blood due to an injury to a blood vessel. An epidural
hematoma can be serious if it is big enough to cause enough pressure on
the spinal nerves so that they quit working. This can cause problems
with the bowels and bladder.
Because the epidural injection actually paralyzes the nerves to the
bowel and bladder for a short period, you may not have control over your
bladder for one to two hours.
There is always a small risk of damage to the spinal nerves. The spinal
cord is a bundle of millions of nerves that connects the brain with the
rest of the body. If the epidural needle directly injures the spinal
nerves, this can cause serious neurologic problems.
Facet Joint Injections
joint injections are used to localize and treat low back pain that is
caused by problems of the facet joints. These joints are located on each
side of the vertebrae; they join the vertebrae together and allow the
spine to move with flexibility. The facet joint injections form a pain
block that allows the doctor to confirm that it is a facet joint causing
the pain. The medication used also decreases inflammation of the joint
that occurs with arthritis and joint degeneration.
insure that an injection is actually into the facet joint,
"fluoroscopy" can be used to confirm that the needle is in the right
position before the medication is injected. A fluoroscope uses X-rays to
show a TV image, so the doctor can watch as the needle is placed into
the joint. The fluoroscope can also magnify the image, increasing
There are two types of facet joint injections:
- Interarticular: This is injected directly into the joint to block the pain and reduce inflammation.
- Nerve Blocks: These help determine whether the joint is
indeed a source of pain by blocking the medial branch or
the nerves that connect with the joint.
Indications to use a facet joint injection:
facet joint injection is perhaps the best way to diagnose facet joint
syndrome. Joints that may look abnormal on an X-ray may in fact be
painless, and joints that look fine may indeed be the source of the
pain; only the injection tells the true story. These injections may be
used to treat low back pain and determine whether the facet joints are
the true culprits. It is also a rather simple procedure with low risk.
Sacroiliac Joint Injections
(SI) joint pain is easily confused with back pain from the spine. The
SI joint is located between the sacrum and the hipbone. In some cases,
injecting the SI joint with lidocaine may help your doctor determine
whether it is the source of pain or not. If the joint is injected and
your pain does not go away, it is probably coming from somewhere else.
If the pain goes away immediately, your doctor may also inject cortisone
into the joint before removing the needle. The cortisone is added to
treat the inflammation from the SI joint arthritis that may be causing
your pain. The cortisone injection usually gives temporary relief
for several weeks or months.
Indications to use a sacroiliac joint injection:
joint injections can be used to prove that the SI joint is the source
of pain and subsequently to treat that pain. This injection usually
requires the use of fluoroscopic guidance or a CAT scan (computed axial
tomography scan) in order to make sure the needle is placed
correctly in the joint. CAT scans are X-ray tests that produce X-ray
slices taken of the spine, so each section can be examined separately.
Differential Lower Extremity Injections
types of injections into certain areas of the lower extremities can
help your doctor decide where the pain is most likely coming from. Pain
that comes from problems with the back and the spinal nerves can mimic
many other conditions. Sometimes it is impossible to tell if the pain
you are experiencing is due to a back condition or from a problem in
your hip, knee, or foot. To try to determine whether the joint is
causing your pain or not, your doctor may suggest injecting medication
such as lidocaine into the joint to numb the area. Once the medication
is injected, if the pain goes away immediately, it is likely that that
joint - not your back - is the source of the pain.
times, your doctor may need to determine whether the metal hardware
that has been used during surgery could be contributing to your
discomfort. A hardware injection is performed by injecting lidocaine
alongside the spinal hardware that was placed in the spine during
surgery. If the pain is relieved temporarily by the injection, it may
indicate that the hardware is contributing to your pain and whether it
needs to be surgically removed.